Remote stereocontrol using rotationally restricted amides: (1,5)-asymmetric induction
作者:Jonathan Clayden、Megan Darbyshire、Jennifer H. Pink、Neil Westlund、Francis X. Wilson
DOI:10.1016/s0040-4039(97)10289-1
日期:1997.12
The stereochemical influence of a rotationallyrestricted amide group extends widely across substituted aromatic amides. Stereogenic centres can be created with high levels of (1,5)-stereocontrol when electrophiles are added to the enolates of 2-ketonaphthamides or to lithiated 2-alkylnaphthamides. Sequential double lateral lithiation of 2,6-dialkylbenzamides can lead to compounds containing (1,5)
Atroposelective attack of nucleophiles and electrophiles on 2-acyl-1-naphthamides and their enolates
作者:Jonathan Clayden、Neil Westlund、Roy L. Beddoes、Madeleine Helliwell
DOI:10.1039/b000668h
日期:——
Organolithiums, Grignard reagents and borohydride reducing agents attack 2-acyl-1-naphthamides to give tertiary and secondary alcohols with high or complete atroposelectivity. High levels of stereoselectivity can also be obtained in the alkylations of enolates derived from the same ketones, though the low barrier to thermal epimerisation of the product ketones prevents accurate determination of the kinetic stereoselectivity of the alkylation. The direction of attack in both cases is controlled by the perpendicular conformation of the aromatic amide substituent, whose NR2 group shields one face of the ketone.